If I try to start the PC within 40 mins of it being shut down, it fails to boot. the board and fans power up but no screen signal or power to ext peripherals (keyboard, mouse). If left longer than 40 mins the PC boots normally.
Also, it 'Restarts' normally from the Start>Shutdown menu, but if you select 'sleep' the PC goes to sleep but crashes (as described above) when you attempt to wake it.
Any ideas of the culprit
I thought about it being heat related but discarded it as the OP says that if you use Restart instead of Shut Down it fires up normally so I wondered about either the Power Supply itself or the CMOS battery. Thinking that if you shut down it loses all the BIOS settings. But even so 40 minutes seems an awfully long wait.
Thanks for all the replies folks.
All the fans are clean and running fine. There is no obvious heat issue (been monitored with HWMonitor).
CMOS battery is new. The OS is Win 7 home premium. It is a desktop.
30 to 40 mins is how long it has to be left before it will start properly after being turned on and then shutdown.
Trying to borrow a PSU to try. Will try the advice from jollyjohn regarding disconnecting the psu and holding down the power button.
This thread is now locked and can not be replied to.